As reinforcing tapes adhered to ends of fastener tapes, there are various types of conventionally known reinforcing tapes. For example, there are known reinforcing tapes that is used by being stacked with transparent synthetic resin films to realize seeing through the color of a dyed fastener tape in order to cut out the need of dyeing into different colors of reinforcing tapes to match with the color of such a dyed fastener tape, and in order to omit the trouble of stock management; and for example, reinforcing tapes as disclosed in patent document 1, obtained as a horizontally pasted reinforcing tape that is formed by stacking transparent polyester copolymer films having a melting point of below 200° C. on one of the surface of a transparent nylon-6 or nylon-66 film in order to make the reinforcing tape visible through the pattern of the base cloth of a fastener tape.
The reinforcing tape containing a two-layer synthetic resin film disclosed in the patent document 1 is hard in material itself, so that it is difficult to be bent to a shape in a manner consistent with the shape of a fastener tape core for attaching metal pieces such as a separable fitting. Therefore, the core of the fastener tape is difficult to be formed into an accurate shape. Furthermore, the following problem exists: the bent portion will be whitened if the reinforcing tape is repeatedly bent, so as to lose its beautiful appearance.
To solve such a problem, as recorded in patent documents 2 and 3, the present applicant developed a reinforcing tape which uses a transparent polyester-based film on a surface layer and is formed by stacking an adhesive layer on a rear surface. In such a reinforcing tape, the surface layer (reinforcing layer) is formed by a polyester-based film, so the reinforcing tape has the following advantages: in comparison to the reinforcing tape formed from a synthetic resin film, this reinforcing tape has flexibility and is easy to be bent to match the shape of a core of a fastener tape, and the like. However, in the case of using a film as a reinforcing layer, there are the following problems when a flexible film with good flexibility and transparency is used: the washing resistance or the resistance to dry cleaning is poor; the reinforcing tape is easy to be swelled if a product equipped with a fastener tape is washed or dry cleaned, so that the peel strength between the reinforcing tape and the fastener tape is reduced and the reinforcing tape is easy to be peeled off.